(1/x-y-1/x+y)÷2y/x²-2xy+y²,其中x=√2+1,y=1-√2

问题描述:

(1/x-y-1/x+y)÷2y/x²-2xy+y²,其中x=√2+1,y=1-√2

=2y/(x^2-y^2) / 2y/(x-y)^2=(x-y)^2 / [(x-y)*(x+y)] = 8/ 4√2= √2

(1/x-y-1/x+y)÷2y/x²-2xy+y²
=2y/(x²-y²)÷2y/(x-y)²
=(x-y)/(x+y)